A Case Study on Testing CMM Uncertainty Simulation Software (VCMM)

Virtual Coordinate Measuring Machines (VCMMs) are software packages aimed at providing uncertainty estimates for tridimensional measurements. Since they deal with metrology data to derive uncertainty estimates, which are to be used for making decisions related to product quality, they must be evaluated. Although there are international standards to deal with software testing for metrology, the evaluation of VCMMs performance is still in the experimental stage. Here a testing framework was organized focusing on the definition of the test context, the test purpose, the performance criteria and the testing strategy, including the usability of the VCMM interface, which is a common focus in software engineering but not in tests of metrology applications. Experimentation and reference data were also used to check the adequacy of uncertainty estimates against measurement results. The executed tests show that it is possible to provide the necessary evidence of acceptable VCMM performance. It is also demonstrated that no single testing strategy is sufficient to provide the necessary evidence to validate the VCMM from the metrology standpoint.